They know why they were banned. They can review the rules that are clearly posted in all forums. Also, sometimes.. as a parting shot.. it might be mentioned in their "revised" sig.
Also.. to tell you honestly.. we usually simply delete/ignore these pm's that are sent usually from the banned persons NEW multiple account.
If the Account that is requesting this info isn't the original poster who was banned.. all this does.. is draw attention to your account. I've said it before.. but it bears repeating... it's none of your business.
It's not worth your time or effort to ask.
It's also not worth our time to provide you with an answer. No answer we provide will satisfy you anyways in most respects.. since bias is with the "banned". After all.. I/we the staff.. are the 'evil' ones who banned you or your 'friend'.
You can chalk up this reply to arrogance.. ego.. whatever. It matters not. It's simply a clarification.